About this world
HD 177565 b is a Neptune-like planet orbiting HD 177565, a yellow, Sun-like star (type G8V) 55.2 light-years from Earth. It is about 4 times the size of Earth (its size estimated from its mass), with at least 15 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 44.5 days at 0.25 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 539 K (266 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2017 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.